The present invention relates to nonwoven fibrous elastic material (e.g., a nonwoven fibrous elastic web), including reinforced elastic material, wherein the nonwoven fibrous elastic material is a hydraulically entangled conform (e.g., admixture) of meltblown fibers and fibrous material (for example, meltblown fibers of an elastomeric material and at least one of (1) pulp fibers, (2) staple fibers, (3) meltblown fibers and (4) continuous filaments), with or without particulate material; nonwoven material including laminates of such nonwoven fibrous elastomeric web attached to a film or fibrous web; and methods of forming such material.
It has been desired to provide a coform which has increased strength and structural integrity, and, depending on the materials utilized, which can be made low linting and highly absorbent, with excellent hand, drape, and anisotropic stretch and recovery properties. It has also been desired to provide such coform, which can be produced relatively inexpensively. Such coform would have wide use in a range of applications, including wipes, absorbent inserts and outer covers for diapers, feminine napkins and incontinence articles, bibs, bed mattress pads, terry cloth and various durables, including garments.
U.S. Pat. No. 4,100,324 to Anderson, et al., the contents of which are incorporated herein by reference, discloses a nonwoven fabric-like composite material which consists essentially of an air-formed matrix of thermoplastic polymer microfibers having an average fiber diameter of less than about 10 microns, and a multiplicity of individualized wood pulp fibers disposed throughout the matrix of microfibers and engaging at least some of the microfibers to space the microfibers apart from each other. This patent discloses that the wood pulp fibers can be intertwined by and held captive within the matrix of microfibers by mechanical entanglement of the microfibers with the wood pulp fibers achieved during incorporation and deposition of the wood pulp fibers and meltblown fibers; and that the mechanical entanglement and intertwining of the microfibers and wood pulp fibers alone, without additional bonding such as adhesive bonding, thermal bonding, additional mechanical bonding, etc., forms a coherent integrated fibrous structure. This patent further discloses that the strength of the web can be improved by embossing the web either ultrasonically or at an elevated temperature so that the thermoplastic microfibers are flattened into a film-like structure in the embossed areas. Additional fibrous and/or particulate materials, including synthetic fibers such as staple nylon fibers and natural fibers such as cotton, flax, jute and silk can be incorporated in the composite material. The material is formed by initially forming a primary air stream containing meltblown microfibers, forming a secondary air stream containing wood pulp fibers (or wood pulp fibers and other fibers; or wood pulp fibers and/or other fibers, and particulate material), merging the primary and secondary streams under turbulent conditions to form an integrated air stream containing a thorough mixture of the microfibers and added fibers, such as wood pulp fibers, etc., and then directing the integrated air stream onto a forming surface to air-form the fabric-like material. A wide variety of thermoplastic polymers are disclosed in Anderson, et al. as being useful for forming the meltblown microfibers, such materials including polypropylene and polyethylene, polyamides, polyesters such as polyethylene eerephthalate and thermoplastic elastomers such as polyurethanes. This patent discloses that by appropriate selection of thermoplastic polymers, materials with different physical properties can be fashioned. However, the product produced by Anderson, et al., particularly when further bonded, lacks the tactile and visual aesthetics necessary for textile materials.
U.S. Pat. No. 4,118,531 to Hauser discloses fibrous webs, and methods of forming such webs, the webs including microfibers and crimped bulking fibers. This patent discloses that the webs are formed by forming the microfibers by a meltblowing technique, admixing the crimped bulking fibers with the microfibers, and then depositing the admixture on a collecting surface. This patent discloses that the fibrous webs are resilient and have good heat insulation properties.
U.S. Pat. No. 3,485,706 to Evans discloses a textile-like nonwoven fabric and a process and apparatus for its production, wherein the fabric has fibers randomly entangled with each other in a repeating pattern of localized entangled regions interconnected by fibers extending between adjacent entangled regions. The process disclosed in this patent involves supporting a layer of fibrous material on an apertured patterning member for treatment, jetting liquid supplied at pressures of at least 200 pounds per square inch (psi) gage to form streams having over 23,000 energy flux in foot-pounds/inch.sup.2.second at the treatment distance, and traversing the supporting layer of fibrous material with the streams to entangle fibers in a pattern determined by the supporting member, using a sufficient amount of treatment to produce uniformly patterned fabric. (Such technique, of using jetting liquid streams to entangle fibers in forming a bonded web material, is herein called hydraulic entanglement.) The initial material is disclosed to consist of any web, mat, batt or the like of loose fibers disposed in random relationship with one another or in any degree of alignment. The initial material may be made by desired techniques such as by carding, random lay-down, air or slurry deposition, etc.; and may consist of blends of fibers of different types and/or sizes, and may include scrim, woven cloth, bonded nonwoven fabrics, or other reinforcing material, which is incorporated into the final product by the hydraulic entanglement. This patent discloses the use of various fibers, including elastic fibers, to be used in the hydraulic entangling. In Example 56 of this patent is illustrated the preparation of nonwoven, multi-level patterned structures composed of two webs of polyester staple fibers which have a web of spandex yarn located therebetween, the webs being joined to each other by application of hydraulic jets of water which entangle the fibers of one web with the fibers of an adjacent web, with the spandex yarn being stretched 200% during the entangling step, thereby providing a puckered fabric with high elasticity in the warp direction.
U.S. Pat. No. 3,494,821 to Evans discloses nonwoven fabrics of staple fibers highly entangled with, for example, continuous filaments or yarns, produced by assembling layers of reinforcing filaments or yarns, and staple-length textile fibers, on a patterning member and hydraulically entangling the fibers by high energy treatment with liquid streams of very small diameter formed at very high pressures.
U.S. Pat. No. 4,426,421 to Nakamae, et al. discloses a multi-layer composite sheet useful as a substrate for artificial leather, comprising at least three fibrous layers, namely, a superficial layer consisting of spun-laid extremely fine fibers entangled with each other, thereby forming a body of a nonwoven fibrous layer; an intermediate layer consisting of synthetic staple fibers entangled with each other to form a body of nonwoven fibrous layer; and a base layer consisting of a woven or knit fabric. The composite sheet is disclosed to be prepared by superimposing the layers together in the aforementioned order and, then, incorporating them together to form a body of composite sheet by means of a needle-punching or water-stream-ejecting under a high pressure. This patent discloses that the spun-laid extremely fine fibers can be produced by the meltblown method.
U.S. Pat. No. 4,209,563 to Sisson discloses a method of making an elastic material, and the elastic material formed by such method, the method including continuously forwarding relatively elastomeric filaments and elongatable but relatively non-elastic filaments onto a forming surface and bonding at least some of the filament crossings to form a coherent cloth which is subsequently mechanically worked, as by stretching, following which it is allowed to relax; the elastic modulus of the cloth is substantially reduced after the stretching resulting in the permanently stretched non-elastic filaments relaxing and looping to increase the bulk and improve the feel of the fabric. Forwarding of the filaments to the forming surface is positively controlled, which the patentee contrasts to the use of air streams to convey the fibers as used in meltblowing operations. Bonding of the filaments to form the coherent cloth may utilize embossing patterns or smooth, heated roll nips.
U.S. Pat. No. 4,426,420 to Likhyani discloses a nonwoven fabric having elastic properties and a process for forming such fabric, wherein a batt composed of at least two types of staple fibers is subjected to a hydraulic entanglement treatment to form a spun laced nonwoven fabric. For the purpose of imparting greater stretch and resilience to the fabric, the process comprises forming the batt of hard fibers and of potentially elastic elastomeric fibers, and after the hydraulic entanglement treatment heat-treating the thus produced fabric to develop elastic characteristics in the elastomeric fibers. The preferred polymer for the elastomeric fibers is poly(butylene terephthalate)-co-poly-(tetramethyleneoxy) terephthalate. The hard fibers may be of any synthetic fiber-forming material, such as polyesters, polyamides, acrylic polymers and copolymers, vinyl polymers, cellulose derivatives, glass, and the like, as well as any natural fibers, such as cotton, wool, silk, paper and the like, or a blend of two or more hard fibers, the hard fibers generally having low stretch characteristics as compared to the stretch characteristics of the elastic fibers. This patent further discloses that the batt of the mixture of fibers that is hydraulically entangled can be formed by the procedures of forming fibers of each of the materials separately, and then blending the fibers together, the blend being formed into a batt on a carding machine.
U.S. Pat. No. 4,591,513 to Suzuki, et al. discloses a fiber-implanted nonwoven fabric, and method of producing such nonwoven fabric, wherein a fibrous web consisting of fibers shorter than 100 mm is laid upon a foamed and elastic sheet of open pore type having a thickness less than 5 mm, with this material then being subjected to hydraulic entangling, while the foamed sheet is stretched by 10% or more, so that the short fibers of the fibrous web may be implanted deeply into the interior of the foamed sheet and not only mutually entangled on the surface of the fibrous web but also interlocked with material of the foamed sheet along the surface as well as in the interior of the foamed sheet. The short fibers can include natural fibers such as silk, cotton and flax, regenerated fibers such as rayon and cupro-ammonium rayon, semi-synthetic fibers such as acetate and premix, and synthetic fibers such as nylon, vinylon, vinylidene, vinyl chloride, polyester, acryl, polyethylene, polypropylene, polyurethane, benzoate and polyclar. The foamed sheet may be of foamed polyurethane.
While the above-discussed documents disclose products and processes which exhibit some of the characteristics or method steps of the present invention, none discloses or suggests the presently claimed process or the product resulting from this process, and none achieves the advantages of the present invention. Thus, the coform web material produced by the process in U.S. Pat. No. 3,100,324 to Anderson, et al., when bonded by further bonding techniques such as adhesives, lacks the aesthetics necessary for the web material to be used advantageously for textile materials. Moreover, the non-woven fabric of U.S. Pat. No. 3,485,706 to Evans uses staple fibers to provide the loose ends necessary for the hydraulic entangling.
Thus, it is desired to provide a nonwoven fibrous elastomeric web material having increased web strength and integrity over known structures. It is further desired to provide a nonwoven fibrous elastomeric web material which is low linting and can be made highly absorbent, which material can have a cloth-like, smooth or textured surface with excellent hand, drape, and isotropic stretch and recovery properties, and barrier properties, depending on the materials utilized in the web, and which material has improved abrasion resistance. It is further desired to provide such material, utilizing a process which is simple and relatively inexpensive.